Lenz's Law states what about the direction of an induced current?

• A. It opposes the change causing it
• B. It reinforces the cause
• C. It aligns with the magnetic field of the earth
• D. It is always counterclockwise

Answer: (A)

Lenz's Law says the induced current in a circuit always flows in a direction that opposes the change in magnetic flux through that circuit. The minus sign in Faraday’s law, emf = -dΦ/dt, encodes this opposition. If the external magnetic flux through the loop is increasing, the loop generates a current whose magnetic field opposes that increase; if the flux is decreasing, the induced field opposes the decrease. A helpful picture: bringing a magnet toward a loop makes the loop's current produce a field that tends to push the magnet away, while removing the magnet makes the loop induce a field that tends to keep the magnet nearby. The actual direction of the current depends on how the flux is changing and the loop’s orientation, so it isn’t always counterclockwise.